1. Technical Field
This invention generally relates to construction materials and techniques, and more specifically relates to a building block, a method for making the building block, and a method for building a wall using the building block.
2. Background Art
Building blocks have been used for centuries to construct homes, office buildings, churches, and many other structures. Early building blocks were hewn from stone into appropriate shapes that were assembled together, typically using mortar, to form a wall. In modern times, various types of concrete blocks were developed, which are typically formed by pouring a cement mixture into a form and allowing the cement to harden. This type of cement block is strong and makes for a sturdy wall, but installing a traditional concrete block requires a skilled mason that places mortar in all joints between blocks to secure the blocks in place.
Various different block configurations have been developed that allow mortar to be poured into inner passageways of the blocks once the blocks have been constructed into a wall. Some of these eliminate the need for a mason to apply mortar between the blocks as the blocks are laid because the blocks are interlocked using mortar poured into interior passages. Examples of blocks with inner passages are found in U.S. Pat. No. 4,295,313, "Building Blocks, Wall Structures Made Therefrom, and Methods of Making the Same", issued Oct. 20, 1981 to Rassias; U.S. Pat. No. 4,319,440, "Building Blocks, Wall Structures Made Therefrom, and Methods of Making the Same", issued Mar. 16, 1982 to Rassias; U.S. Pat. No. 2,701,959, "Sectional Block Masonry", issued Feb. 15, 1955 to Briggs; and Swiss Patent No. 354237, issued Jun. 30, 1961.
One significant drawback of using concrete blocks to form walls in a structure is that surficial covering material often needs to be applied to the surface of the walls. Many common surficial coverings for walls are attached using nails or screws. For example, siding may need to be applied to the outside of the wall, and wallboard, paneling, or other sheet material may need to be applied to the inside of the wall. Known concrete blocks are too hard and brittle to allow commonly-used nails or screws to be used to attach a surficial covering material. As a result, special concrete nails or anchors are typically used to secure wood furring strips or studs to the concrete block wall, and the covering materials are, in turn, fastened to the furring strips or studs. This process of fastening wood furring strips or studs to the block wall and nailing on the covering material to the furring strips is time-consuming, and the concrete blocks do not hold the nails or anchors in place very well. It is not uncommon for one or more of the concrete nails to become loose when a surficial material is nailed in place, compromising the structural integrity of the wall.
Therefore, there existed a need to provide an improved building block with an attachment layer that allows covering materials to be directly attached to the building blocks using conventional nails, screws, or staples.